This invention relates to analog video network systems and more particularly to analog video network systems having a plurality of video cameras and employing analog video printers, and most particularly to such systems that are usable in the field of dentistry, especially for forensic applications.
In the field of dentistry and in other medical sciences, it is often necessary to use a video camera to view an area of interest of a patient and display that area on a monitor. It is also often necessary to produce a printout of the video image by such a video system, in order to create a permanent record for a file.
In many instances, use of such video images in dentistry and other medical sciences, and especially the recording of such images by way of printing, is for forensic purposes. For reasons of legality, it is not permissible for video printouts used for forensic purposes to be altered in any manner. An exact unaltered replica of the image captured by the video camera must be produced by the video image printer.
As is well known in the art, it is quite possible to tamper with a digital image and thereby produce a resulting image without any evidence of tampering. However, in direct contrast, if an analog signal is tampered with, either the resulting image would be unrecognizable or it would be very apparent that tampering had occurred. Accordingly, an analog video printer must be used for forensic purposes in order to ensure that the resulting printed image is an accurate representation of what is being viewed by the video camera and also shown on the video monitor.
Modern dental operatories have a number of stations, with each station having a video camera, a video monitor, and an analog video printer. Such analog video printers are very expensive, thus very significantly increasing the cost of such dental operatories or possibly even limiting the number of these types of stations that dental operatories can afford to operate.
It is highly desirable for economic reasons to maximize the number of stations in a dental operatory that use a single analog video printer, or in an alternative sense, provide a means for permitting a single analog video printer to be used in a dental operatory.
U.S. Pat. No. 6,091,881 issued Jul. 18, 2000 to KAMIKUBOTA, discloses a Video Printer wherein two analog input sources comprising both video and audio are fed into an analog printer. A selectively operable switch permits selection of either of the two analog input sources for printing. A monitor is a connected to an analog output of the printer and another selectively operable switch permits viewing of either of the inputs, but only input one at a time. Accordingly, this system could not be used in the field of dentistry or other medical applications where more than one video input is used.
U.S. Pat. No. 6,097,902 issued Aug. 1, 2000 to BLUME, discloses an Enhanced Device for Producing Analog and Digital Images from Dental Radiographic Film and Process for Using the Same. The camera is connected to the input of a video amplifier. The output of the video amplifier is connected to an analog monitor and is also connected to a computer where it is converted from an analog signal to a digital signal. A digital monitor and conventional digital printer are connected to the computer. As discussed above, since the image is in digital format, it can be quite readily altered within the computer, without such alterations being discernible when the image is printed out.
U.S. Pat. No. 5,926,285 issued Jul. 20, 1999 to TAKAHASHI, discloses an Image Reproduction System for Reproducing a Still Image from Video, wherein a video camera is connected to an analog to digital converter. A switch permits selection between the signal originally from the video camera or from a digital signal from the data bus for routing to a printer.
U.S. Pat. No. 5,293,313 issued Mar. 8, 1994 to CECIL et al., discloses a Real Time Physician View Box for use up with a medical diagnostic imager. The system disclosed therein is significantly more complicated than the system has taught in Blume, and is representative of the very expensive types of image recording and printing systems used in medical sciences.
It is an object of the present invention to provide an analog video network system for producing a recorded output of a video image, preferably a printed output, which analog video network system permits a single analog video printer to be used by a number of stations each having a video camera and a video monitor.
In accordance with one aspect of the present invention, there is provided a novel analog video network system for producing a recorded output of a video image. The analog video network system comprises a video camera for producing an analog video signal corresponding to a video image; a video monitor for receiving the analog video signal and displaying a video image according to the analog video signal; and an analog video output device for receiving the analog video signal and producing a recorded output according to the analog video signal, which output is a functional replica of the video image. A relay, in an inactive state, connects the video camera to the video monitor so as to cause the video monitor to display the video image; and, in an active state, the relay connects the video camera to the video monitor through the analog video output device so as to cause the analog video output device to produce the recorded output and the video monitor to display the video image. A controller is used for activating and deactivating the relay.
In accordance with another aspect of the present invention, there is provided a novel analog video network system for producing a recorded output of a video image. The analog video network system comprises a first plurality of video cameras, each for producing an analog video signal corresponding to a video image; a first plurality of video monitors for receiving the analog video signal and displaying a video image according to the analog video signal, each video camera being connected to a respective video monitor; an analog video output device for receiving an analog video signal from a selected video camera and producing a recorded output according to the respective received analog video signal, which output is a functional replica of the video image, and a first plurality of relays. In an inactive state, each relay connects one of the video cameras to its respective one of the video monitors, so as to cause the video monitor to display the respective video image; and, in an active state, a selected relay connects a selected one of the video cameras to a corresponding one of the video monitors through the analog video output device so as to cause the analog video output device to produce the recorded output and the video monitor to display the respective video image. A controller is used for selectively activating a selected one of the relays, and for deactivating the remaining ones of the relays.